History of the cell All living organisms are made up of cells.

Cells are: The basic unit of structure and function of a living organism. Organsims can be either: unicellullar multicellular

History of the cell. 1665 Anton van Leevwenhoek: . constructed first simple microscope. viewed pond water and saw tiny moving structures called them “wee little beasties” or “animalcules .

1670 Robert Hooke Inventor of first compound light microscope. Viewed cork Viewed tiny, hollow units and called them “cells”.

Approximately 200 years later… 1833 Robert Brown First to see a nucleus within a cell. They now knew that: cells were not hollow like the cork. that there were structures within the “cells”

1835 Two German scientist, Theodor Schwann (Zoologist) and Matthias Schleiden (Botanist) collectively came to the conclusion that all plants and all animals are made up of cells. 1855 Rudolf Virchow recorded that “all cells come from other like and pre-existing cells.

1869 Fredrick Miescher: discovered DNA’s presence (not its structure) did not know its importance until much later. He called it nuclein. 1879 Walter Flemming: Identified chromosomes in the nucleus. Once again did not know the true importance of them.

The Cell Theory 1. Every living organism is made up of one or more cells. 2. Cells are the basic unit of structure and function of all living organisms. 3. All cells arise from like, pre-existing cells.

Two types of cells exist: Prokaryotic and Eukaryotic Cells

Prokaryotic Cells Word means “before nucleus” Includes all bacteria 1.Believed to be the first cells on Earth in the primordial soup 2. Lack a nucleus and all membrane bound organelles. 3. Genetic material just floats around the center of the cell.

Eukaryotic Cells Word means “contains a true nucleus” Includes all animals, plants, fungi, and protist. Evolved from prokaryotic cells. 1. Theory is one prokaryotic cell engulfed another and now there was a cell within another cell.

2. Eukaryotic cells contain a nucleus and membrane bound organelles. 3. Organelles are “tiny organs” within a cell, each having their own function.

Two types of eukaryotic cells: Plant-like Animal-like

Traits common to both prokaryotic and eukaryotic cells -Plasma / cell membranes -Cytoplasm -Cell wall -Ribosomes -Genetic material

Cell Membrane

Plasma or Cell Membrane: Function: 1. Outer boundary of the cell -separates one cell from another

2. Allows for interaction between like cells within a tissue.

-regulates what is allowed to enter or leave the cell. 3. Acts as a “gatekeeper” -regulates what is allowed to enter or leave the cell. Aids in protection and support. -keeps out bacteria -provides some shape Oxygen Food Molecules Water Carbon dioxide Cellular Waste Excess water

Fluid Mosaic Model -model of the structure of a cell membrane hyperlink -model of the structure of a cell membrane -discovered in 1972

The cell membrane: -Composed of a phospholipid bilayer/double layer of phospholipids with proteins and some carbohydrates scattered throughout it.

Components of the Cell Membrane Carbohydrate chains Used for cell recognition Phospholipid bilayer Type of lipid Contain pores/openings Proteins: - receptor proteins - transporting proteins - adhesion proteins

Phospholipid -type of lipid -most abundant component in the membrane Hydrophilic Head -water loving -polar Hydrophobic Tail -water fearing -nonpolar

Extracellular Fluid: Cells watery environment Intracellular Fluid: Cells liquid center/cytoplasm

Several types of proteins embedded in the bilayer: 1. Receptor proteins: act as a docking area for items to attach to like hormones.

2. Transporting proteins: Hyperlink -transports items across the bilayer

3. Adhesion Proteins: -project outward from bilayer and help cells within a tissue to stick together.

Cytoplasm: 1. -liquid part of the cell 2. -found in all areas between the nucleus and the cell membrane 3.-made mostly of water with salts, amino acids, nucleotides, etc… dissolved in it. Function: -to suspend and allow structures to move about.

Cell Wall: 1.-surrounds cell membrane -found in plants, fungi, some bacteria and some protist. 2.-located outside the cell membrane 3.-provides shape and support

4. -has openings so items can pass through. 5. -made up of cellulose and pectin in plants and chitin in fungi.

Turgor Pressure: 1. -Pressure created by water -cell loses water -turgor pressure decreases -cell wall bows inward -cell shrinks in size

2. Cell takes in water - turgor pressure increases - cell wall bulges out - cell swells

Complete part A and B of Cell Lab

Genetic Material: Prokaryotic Cells: -Have no nucleus 1.-made up of DNA 2.-has instructions for making all cellular proteins. Prokaryotic Cells: -Have no nucleus -DNA is free floating -DNA is in 1 circular loop

Eukaryotic Cells: -DNA contained in a nucleus -many linear pieces of DNA known as chromosomes.

Ribosomes: The cells “workbench” Job: Makes proteins, in their linear form, by assembling amino acids in the correct order based on DNA’s code.

Ribosomes are made up of RNA and proteins. Found attached to the endoplasmic reticulum or Free floating in the cytoplasm

Structures of Eukaryotic Cells -Nucleus and Nucleolus -Mitochondria -Chloroplast -Rough Endoplasmic Reticulum -Smooth Endoplasmic Reticulum -Golgi bodies -Lysosomes -Vacuoles -Plastids -Peroxisomes -Cytoskeleton

Nucleus: 1.-Brain of cell 2.-Cells control center 3.-Contains DNA 4.-Made up of another lipid bilayer 5.-contains pores for items to move in and out.

Nuclear Envelope: -outside of nucleus, studded with pores Nucleolus: -circular structure within nucleus -makes ribosomes Nucleoplasm: -cytoplasm inside the nucleus

Chromatin: 1.-loosely coiled DNA found within the nucleus 2.-can tightly coil into a bow tie shaped “chromosome”

Chromosomes are made up of genes. -segments of DNA which code for specific proteins

Quicktime movie: 4 min

Mitochondria: 1. -cell’s powerhouse 2. -the place were the cell converts food into energy. 3. -found in all eukaryotic cells~plant-like and animal like.

4. -site of cellular respiration sugar + oxygen  ATP energy + carbon dioxide + water Form of energy used by a cell to do “work”. -12 to 1000 mitochondria per cell -plant cells have less than animal cells. Why? -less active -require less energy -Which cells in our body would have the most mitochondria? -muscle cells ~ very active

Mitochondria are made up of 2 membranes: -outer membrane -inner membranes known as cristae.

Cristae increase the surface area so more energy can be produced without taking up too much room. Analogy: Population 5,000 in 1/4 square mile. Population 5,000 in 10 square mile. verses

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Chloroplast: -site of photosynthesis -Found only in plant-like cells Sun + CO2 + H2OC6H12O6 + O2

CHLOROPLAST: -Trap energy of the sun and convert it into sugars which can be stored by the plant or broken down in the mitochondria into ATP energy. Plant store sugar in their fruits, stems, and roots.

Thylakoids: platelike structures which collect the sun’s energy. Grana or Granum: Stacks of thylakoids (10 to 100/chloroplast) Stroma: Liquid part of the chloroplast Lumen: Inside thylakoids ~ contains chlorophyll

ROY G BIV Absorbs: -all spectrums of light but green is reflected.

Complete part C, D and E of Cell lab

Ribosomes Review: The cells “workbench” Job: Makes proteins, in their linear form, by assembling amino acids in the correct order based on DNA’s code.

Ribosomes are made up of RNA and proteins. Attached ribosomes: -attached to the endoplasmic reticulum or Free floating ribosomes: - Floating around in the cytoplasm throughout the cell

Endoplasmic Reticulum (ER): -Known as the “cells subway system -Transports proteins around the cell

The E.R is a made up of a series of interconnected, hollow channels. Two types of E.R: 1. Smooth E.R. -has no ribosomes attached. -responsible for making phospholipids for new membranes 2. Rough E.R. -has ribosomes attached -aids in protein synthesis

1.Proteins, made by the ribosomes, travel through the hollow channels of the rough ER into the smooth ER. 2.The end of the smooth ER pinches off around the protein forming a “transporting vesicle”

3. Transporting vesicle transports the newly formed protein to the golgi body.

Golgi Complex, Apparatus or Bodies -a stack of flattened membranes clustered in one area. Made up of a collection of transporting vesicles.

Known as the Fed-Ex man Job: Collects, stores, modifies and packages materials it receives from the transporting vesicles/ER and then deliver them to where they need to go. -Where a protein gets it 3D shape

Example: Insulin production in a pancreas cell

Lysosomes: Nickname: Clean Up Crew or Suicide Sack Job: Organelles which contain digestive enzymes made by the ribosomes and processed in the golgi. Three Jobs: 1. Fuse to an old or damaged cell organelle, injects its enzymes into it and digest the old organelle .

2. Lysosomes fuse to food and digest the food for the cell. Lysosomes in an older or damaged Cell breaks open and releases enzymes into the Cytoplasm ~ digesting the cell from the inside out. Example: lifespan RBC’s 120 days WBC’s 8 days Sperm 5 days

Lysosomes are rarely found in plant cells. -when plant cells die, parts of the cell remains. Formation of a lysosome: 1. Ribosomes made dig. enzyme 2. Travel through ER 3. Smooth ER pinches off and dig. enzyme is contained in a transporting vesicle. 4. Transporting vesicle fuses with golgi 5. Golgi modifies enzyme giving it a 3D shape 6. Section of golgi moves away with enzyme inside it ~ now a lysosome.

Lysosomes

Vacuoles: Storage area for cell Stores excess water, food or waste.

Plant-like cells have 1 or 2 large central vacuole which stores excess water or sugars Animals-like cells have many small vacuoles which store excess water and waste.

Plastids: specialized vacuoles in plants Chloroplast: Stores chlorophyll Leucoplast: Stores starch Chromoplast: Stores color pigments

Cytoskeleton: cell’s framework = cell = support A woven web-like system embedded into a plant and animal cell’s cell membrane and cytoplasm, provides some support to the cell.

Different animal cells have specific shapes:

Cytoskeleton is made up of both: 1. Microfilaments: -long, solid tubes of proteins -allow for movement within cell tissue like muscles. 2. Microtubules: -long, hollow tubes of protein

Flagella: Long whip like tail Cilia: short hairlike

Centrioles: used by animal cells for cell division

Villi: fingerlike projections or extensions of the cell membrane Villi: fingerlike projections or extensions of the cell membrane. Increases the surface area of the cell’s membrane.

Plant and Animal Cell Comparison Plant cells have: Animal cells have: cell wall and membrane cell membrane chloroplast no chloroplast 1 or 2 large vacuole many small vacuoles No centrioles 1 pair of centrioles Has plastids No plastids Rectangular in shape Roundish in shape Small # of mitochondria Large # of mitochondria

Quicktime movie (6 min)